Ommastrephid funnel/mantle locking-apparatus

The ommastrephid funnel/mantle locking-apparatus is one of the most characteristic features of the family. The funnel component is cartilagenous and contains a longitudinal groove (sulcus) that is swollen posteriorly (pouch) and tapers anteriorly, and posterior transverse grooves. The sulcus is surrounded by the boundary region which may be modified ito form a lip and pad anteriorly. The medial wall of the sulcus is more clearly defined than the lateral wall and generally undercuts the adjacent boundary region for much of its length. Some of the cartilage extends into the funnel muscle to form an anchor and a potion of the anchor extends anteriorly beyond the lock just beneath the integument (appendix). The mantle component has a fibrous construction except anteriorly where some cartilage overlies part of its ridges and grooves.

Figure. Same funnel and mantle components of the funnel locking-apparatus of Ommastrephes bartramii as seen above. The yellow color on the mantle component highlights ridges. These highlights have then been reversed in orientation and overlaid on the funnel component to show how the two components combine. Photographs by R. Young.

Figure. Left - Frontal views of the funnel and mantle components of the funnel locking-apparatus of Sthenoteuthis oualaniensis, immature female, 140 mm ML, Hawaiian waters, stained with methylene blue stain. Note the tissue cut to separate the fused components. The arrow points to a strip of tissue torn out of the mantle when the components were pulled apart but the fusion hadn't been completely cut. Right - Anterior ends of the mantle (top) and funnel (bottom) components, partially destained. Arrows point to cartilages. Photographs by R. Young.

Anterior Sulcal Ridge bordered on either side by broad swelling of muscular mantle wall. Swellings may be artifact or could be homologous with Outer and Inner Ridges of O. bartramii and similar species.

Lateral side of middle Sulcal Ridge with broad taper; medial side of Ridge sharply defined.

Cartilagenous tip covers much of slender, anterior Sulcal Ridge with slight flare along either side.

Anterior Sulcal Ridge bordered on either side by broad swelling of muscular mantle wall. Swellings may be artifact or could be homologous with Outer and Inner Ridges of O. bartramii and similar species.

Sulcal Ridge with medial and lateral edges approximately equally well defined.

Cartilagenous tip covers much of slender, anterior Sulcal Ridge with slight flare along either side.

Anterior Sulcal Ridge bordered on either side by narrow swelling of muscular mantle wall. Swellings may be artifact or could be homologous with Outer and Inner Ridges of O. bartramii and similar species.

Lateral side of middle Sulcal Ridge with broad taper; medial side of Ridge sharply defined.

Cartilagenous tip covers much of slender, anterior Sulcal Ridge and much of posterolateral region up outer swelling.

Figure. Left - Frontal views of the funnel and mantle components of the funnel locking-apparatus of Todarodes pacificus, immature male, 214 mm ML, Japanese waters, stained with methylene blue stain. The hole in the pouch is due to damage during preparation. Right - Anterior ends of the mantle (top) and funnel (bottom) components, partially destained. Arrows point to cartilages. Skin removed over Appendix. Photographs by R. Young.

Todaropsis eblanae

Funnel component

Anterior end nearly symmetrical.

Sulcus very short, narrows distally but Sulcus and Pouch form straight line that strongly tilts medially.

Anterior Sulcal Ridge bordered on either side by narrow swelling of muscular mantle wall. Swellings may be artifact or could be homologous with Outer and Inner Ridges of O. bartramii and similar species.

Lateral side of middle Sulcal Ridge with steep taper; medial side of Ridge sharply defined.

Cartilagenous tip covers much of slender, anterior Sulcal Ridge and extends well into area between Sulcal Rdige and outer swelling.

Figure. Left - Frontal views of the funnel and mantle components of the funnel locking-apparatus of Martialia hyadesi, immature female, 180 mm ML, western South Atlantic, stained with methylene blue stain. Right - Anterior ends of the mantle (top) and funnel (bottom) components, partially destained. Arrows point to cartilages. Skin removed over Appendix. Photographs by R. Young.

Comments

This first look at the comparison of the locking-apparatus of all genera of Ommastrephidae lacks knowledge of the variation at intraspecific and intrageneric levels. The differences seen here, therefore, must be used cautiously.

The higher ommastrephinae (Dosidicus, Sthenoteuthis, Ommastrephes, Eucleoteuthis and Hyaloteuthis) all exhibit considerable similarities in their locks. All have mantle components with bifurcate anterior ends or their remnants and a tripartite distal cartilage. Dosidicus, Sthenoteuthis and Ommastrephes each have a strongly asymmetrical anterior end of the funnel component. The most divergent of these five genera is Hyaloteuthis which may be a result of its small size. Ornithoteuthis, Illex and Nototodarus all have simple locks. Illex appears to be distinguished by the near lack of asymmetry between the medial and lateral sides of the Sulcus and Sulcal Ridge. Todarodes and Martialia share similarities in the anterior cartilage of their mantle components. Todaropsis is distinctive in its short Sulcus and Sulcal Ridge. Both Todaropsis and Nototodarus have the mantle component terminating anteriorly well short of the anterior mantle edge. Also there is considerable differences in the size and shape of the cartilagenous Appendix in some genera.

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Page: Tree of Life
Ommastrephid funnel/mantle locking-apparatus
Authored by
Richard E. Young and Michael Vecchione.
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